1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) 2017 Google, Inc.
4  */
5 
6 #ifndef _LINUX_BINDER_ALLOC_H
7 #define _LINUX_BINDER_ALLOC_H
8 
9 #include <linux/rbtree.h>
10 #include <linux/list.h>
11 #include <linux/mm.h>
12 #include <linux/rtmutex.h>
13 #include <linux/vmalloc.h>
14 #include <linux/slab.h>
15 #include <linux/list_lru.h>
16 #include <uapi/linux/android/binder.h>
17 
18 extern struct list_lru binder_freelist;
19 struct binder_transaction;
20 
21 /**
22  * struct binder_buffer - buffer used for binder transactions
23  * @entry:              entry alloc->buffers
24  * @rb_node:            node for allocated_buffers/free_buffers rb trees
25  * @free:               %true if buffer is free
26  * @clear_on_free:      %true if buffer must be zeroed after use
27  * @allow_user_free:    %true if user is allowed to free buffer
28  * @async_transaction:  %true if buffer is in use for an async txn
29  * @oneway_spam_suspect: %true if total async allocate size just exceed
30  * spamming detect threshold
31  * @debug_id:           unique ID for debugging
32  * @transaction:        pointer to associated struct binder_transaction
33  * @target_node:        struct binder_node associated with this buffer
34  * @data_size:          size of @transaction data
35  * @offsets_size:       size of array of offsets
36  * @extra_buffers_size: size of space for other objects (like sg lists)
37  * @user_data:          user pointer to base of buffer space
38  * @pid:                pid to attribute the buffer to (caller)
39  *
40  * Bookkeeping structure for binder transaction buffers
41  */
42 struct binder_buffer {
43 	struct list_head entry; /* free and allocated entries by address */
44 	struct rb_node rb_node; /* free entry by size or allocated entry */
45 				/* by address */
46 	unsigned free:1;
47 	unsigned clear_on_free:1;
48 	unsigned allow_user_free:1;
49 	unsigned async_transaction:1;
50 	unsigned oneway_spam_suspect:1;
51 	unsigned debug_id:27;
52 	struct binder_transaction *transaction;
53 	struct binder_node *target_node;
54 	size_t data_size;
55 	size_t offsets_size;
56 	size_t extra_buffers_size;
57 	unsigned long user_data;
58 	int pid;
59 };
60 
61 /**
62  * struct binder_shrinker_mdata - binder metadata used to reclaim pages
63  * @lru:         LRU entry in binder_freelist
64  * @alloc:       binder_alloc owning the page to reclaim
65  * @page_index:  offset in @alloc->pages[] into the page to reclaim
66  */
67 struct binder_shrinker_mdata {
68 	struct list_head lru;
69 	struct binder_alloc *alloc;
70 	unsigned long page_index;
71 };
72 
73 static inline struct list_head *page_to_lru(struct page *p)
74 {
75 	struct binder_shrinker_mdata *mdata;
76 
77 	mdata = (struct binder_shrinker_mdata *)page_private(p);
78 
79 	return &mdata->lru;
80 }
81 
82 /**
83  * struct binder_alloc - per-binder proc state for binder allocator
84  * @mutex:              protects binder_alloc fields
85  * @mm:                 copy of task->mm (invariant after open)
86  * @vm_start:           base of per-proc address space mapped via mmap
87  * @buffers:            list of all buffers for this proc
88  * @free_buffers:       rb tree of buffers available for allocation
89  *                      sorted by size
90  * @allocated_buffers:  rb tree of allocated buffers sorted by address
91  * @free_async_space:   VA space available for async buffers. This is
92  *                      initialized at mmap time to 1/2 the full VA space
93  * @pages:              array of struct page *
94  * @buffer_size:        size of address space specified via mmap
95  * @pid:                pid for associated binder_proc (invariant after init)
96  * @pages_high:         high watermark of offset in @pages
97  * @mapped:             whether the vm area is mapped, each binder instance is
98  *                      allowed a single mapping throughout its lifetime
99  * @oneway_spam_detected: %true if oneway spam detection fired, clear that
100  * flag once the async buffer has returned to a healthy state
101  *
102  * Bookkeeping structure for per-proc address space management for binder
103  * buffers. It is normally initialized during binder_init() and binder_mmap()
104  * calls. The address space is used for both user-visible buffers and for
105  * struct binder_buffer objects used to track the user buffers
106  */
107 struct binder_alloc {
108 	struct mutex mutex;
109 	struct mm_struct *mm;
110 	unsigned long vm_start;
111 	struct list_head buffers;
112 	struct rb_root free_buffers;
113 	struct rb_root allocated_buffers;
114 	size_t free_async_space;
115 	struct page **pages;
116 	size_t buffer_size;
117 	int pid;
118 	size_t pages_high;
119 	bool mapped;
120 	bool oneway_spam_detected;
121 };
122 
123 #ifdef CONFIG_ANDROID_BINDER_IPC_SELFTEST
124 void binder_selftest_alloc(struct binder_alloc *alloc);
125 #else
126 static inline void binder_selftest_alloc(struct binder_alloc *alloc) {}
127 #endif
128 enum lru_status binder_alloc_free_page(struct list_head *item,
129 				       struct list_lru_one *lru,
130 				       void *cb_arg);
131 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
132 					   size_t data_size,
133 					   size_t offsets_size,
134 					   size_t extra_buffers_size,
135 					   int is_async);
136 void binder_alloc_init(struct binder_alloc *alloc);
137 int binder_alloc_shrinker_init(void);
138 void binder_alloc_shrinker_exit(void);
139 void binder_alloc_vma_close(struct binder_alloc *alloc);
140 struct binder_buffer *
141 binder_alloc_prepare_to_free(struct binder_alloc *alloc,
142 			     unsigned long user_ptr);
143 void binder_alloc_free_buf(struct binder_alloc *alloc,
144 			   struct binder_buffer *buffer);
145 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
146 			      struct vm_area_struct *vma);
147 void binder_alloc_deferred_release(struct binder_alloc *alloc);
148 int binder_alloc_get_allocated_count(struct binder_alloc *alloc);
149 void binder_alloc_print_allocated(struct seq_file *m,
150 				  struct binder_alloc *alloc);
151 void binder_alloc_print_pages(struct seq_file *m,
152 			      struct binder_alloc *alloc);
153 
154 /**
155  * binder_alloc_get_free_async_space() - get free space available for async
156  * @alloc:	binder_alloc for this proc
157  *
158  * Return:	the bytes remaining in the address-space for async transactions
159  */
160 static inline size_t
161 binder_alloc_get_free_async_space(struct binder_alloc *alloc)
162 {
163 	size_t free_async_space;
164 
165 	mutex_lock(&alloc->mutex);
166 	free_async_space = alloc->free_async_space;
167 	mutex_unlock(&alloc->mutex);
168 	return free_async_space;
169 }
170 
171 unsigned long
172 binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
173 				 struct binder_buffer *buffer,
174 				 binder_size_t buffer_offset,
175 				 const void __user *from,
176 				 size_t bytes);
177 
178 int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
179 				struct binder_buffer *buffer,
180 				binder_size_t buffer_offset,
181 				void *src,
182 				size_t bytes);
183 
184 int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
185 				  void *dest,
186 				  struct binder_buffer *buffer,
187 				  binder_size_t buffer_offset,
188 				  size_t bytes);
189 
190 #endif /* _LINUX_BINDER_ALLOC_H */
191 
192